The present invention relates to release agent compositions which are particularly useful for frozen food products and to methods for using such compositions in relatively low temperature environments. The release agent compositions in accordance with the present invention comprise at least one oil having specified congealing characteristic and fatty acid unsaturation levels which is blended with lecithin and mineral oil of a prescribed grade and viscosity to provide a blend which will remain liquid even at sub-freezing temperatures for relatively long time periods.
The freezing of foods, whether in their finished form or intermediary form, is becoming recognized as one of the best ways to guarantee that the food will maximally retain its natural taste, texture, color, and freshness even when stored for many months. In the field of food processing, the use of release coatings has long been recognized as an effective way to reduce production costs by limiting food waste. In fact, effective release agents are becoming more and more critical to a successful operation of a completely automated processing procedure.
Many large frozen food processing plants are high production, completely automated plants, where having a carefully designed release agent would make a substantial contribution to speed and efficiency of the manufacturing process. For example, when a conveyor belt reaches the end of its line, all goods must fall off to insure the proper functioning of the overall automated process. Moreover, release agent compositions would be beneficial from a retail standpoint because many consumers prefer food products that neither stick together nor adhere too tightly to surfaces of associated packaging materials.
In general, most processed foods have either natural moisture or juices or have had these ingredients imparted to the food during processing procedures. Often, water is applied just prior to freezing the food to produce a glaze of ice which acts as a protective barrier for the frozen products. However, when the moisture or juices freeze, this often produces sticking to processing and conveying equipment surfaces and in some cases, sticking of products to each other. Such surfaces include solid and wire mesh freezer conveyor belts, freezing trays, elevator buckets, holding tubs, and the like.
Moreover, it is desirable, if not necessary, in many instances, to provide a mechanism which will release frozen food from sidewalls of a package to insure that proper taste, texture, and other desired properties are preserved from processer to consumer. In some instances, a release agent coating on individual pieces of frozen food which are packaged together, for instance in a boilable bag, is desired to insure that the frozen food products will not stick to each other during boiling. In this respect, an important feature of the release agent composition is that it be capable of producing a uniform coating, for instance by means of a spray nozzle, to provide consistency within processing parameters. Further, the release agent composition must not clog or otherwise hamper the equipment which applies the release agent coating to the product.
The problem of sticking between material surfaces in contact is particularly severe in the frozen food industry where moisture present on the outer surface of the product will freeze and act as a cementing agent. Freeing material surfaces which are undesirably stuck together in low temperature environments is usually accomplished by mechanical means, but this mechanism is generally inefficient and often results in marred or broken product surfaces, and sometimes, products which are no longer sellable.
A variety of release compositions are known to those skilled in the art. These are usually vegetable oil or fat based compositions which are not able to provide lubrication over a full temperature range especially relatively low temperature. In this regard, while these compositions alleviate sticking problems encountered during normal processing temperatures (from about 55.degree. F. to about 450.degree. F.), they are usually inadequate at temperatures below freezing.
An alternative means to minimize adhesion between contacting material surfaces involves placing waxed or silicone treated papers between the frozen products, as for example, between frozen hamburger patties. While this means is sometimes acceptable, it is relatively expensive and impractical for many foods.
Accordingly, release agents capable of withstanding cold temperature, below freezing, without significant congealing or hardening and producing a uniform coating to applied material surfaces has been recognized by those skilled in the art as a need in many processing industries, particularly frozen food processing. The present invention fulfills this need.